add numerical recipes library

lib/nr/cpp/recipes/hpsort.cpp

@@ -0,0 +1,34 @@
+#include "nr.h"
+
+namespace {
+	void sift_down(Vec_IO_DP &ra, const int l, const int r)
+	{
+		int j,jold;
+		DP a;
+
+		a=ra[l];
+		jold=l;
+		j=l+1;
+		while (j <= r) {
+			if (j < r && ra[j] < ra[j+1]) j++;
+			if (a >= ra[j]) break;
+			ra[jold]=ra[j];
+			jold=j;
+			j=2*j+1;
+		}
+		ra[jold]=a;
+	}
+}
+
+void NR::hpsort(Vec_IO_DP &ra)
+{
+	int i;
+
+	int n=ra.size();
+	for (i=n/2-1; i>=0; i--)
+		sift_down(ra,i,n-1);
+	for (i=n-1; i>0; i--) {
+		SWAP(ra[0],ra[i]);
+		sift_down(ra,0,i-1);
+	}
+}